well... it's fairly simple, really. haze is good for far away stuff. mainly it is for blurring the line between the sky and horizon. you pick a haze colour (usually it is light blue or greyish), and crank up the dial for more haze. it's kinda like the difference between a clear day and a foggy or humid day. if you do like i do, and make 'forced perspective' landscapes (ie: those distant mountains aren't as distant as they look, they're just scaled that way), haze may not fog out your stuff the way you want it to. in this case, use distance fog. pick a colour just like you did for haze. then slide the amount slider over. watch the little enigmatic picture of the line that kinda makes a backwards checkmark squeeze together. the line on the left represents the front of the fog bank, and the line on the right... i think that represents the picture plane where the camera is. so as you increase the fog, you're moving it towards the camera, and can even cover up the camera and go beyond it. well, anyway, i usually play with the sliders, then do a quick render to see where the fog ended up, or if the haze hazed out my stuff yet. ;)